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A Sensitive Radiometric Assay for Tryptophan Hydroxylase Applicable to Crude Extracts
Author(s) -
Beevers S. Jane,
Knowles Richard G.,
Pogson Christopher I.
Publication year - 1983
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1983.tb08066.x
Subject(s) - tryptophan , chemistry , enzyme , chromatography , activated charcoal , substrate (aquarium) , tryptophan hydroxylase , enzyme assay , biochemistry , amino acid , biology , organic chemistry , ecology , receptor , adsorption , serotonergic , serotonin
We describe here a simple and convenient method for assay of tryptophan 5‐monooxygenase (hydroxylase), applicable to enzyme in all states of purification. It is based on the enzyme‐catalysed formation of 5‐hydroxy‐[4‐ 3 H]tryptophanfrom [5‐ 3 H]tryptophan, and the subsequent acid‐dependent quantitative release of 3 H as 3 H 2 O; unreacted substrate is removed with activated charcoal. The assay is linear with respect to both protein concentration and time, and gives results similar to those in a standard fluorimetric assay.